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A seminar report on stps by ashok khoja
 

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    A seminar report on stps by ashok khoja A seminar report on stps by ashok khoja Document Transcript

    • A Seminar Report On SURATGARH SUPER THERMAL POWER STATION Submitted in partial fulfillment for the Award of degree of Bachelor of Technology In Electrical Engineering 2012-13Submitted By: Submitted To:Name of Student- ASHOK KHOJA Mr. Manoj ChhimpaRoll No:- 05 Assistant ProfessorB.Tech, Final year Deptt.of Electrical Engg. Department of Electrical Engineering GOVT. ENGINEERING COLLEGE BIKANER i
    • ii
    • ACKNOWLEDGEMENTI Ashok Khoja 4th year student of ENGINEERING COLLEGE BIKANERconsider training to be a challenging job and the completion Of my practical training, I wouldlike to thank all the personalities who have helped me in the completing the work.I greatly thankful the help of :Department: :Mr. MANOJ CHHIMPA, Mr. NAVIN PALIWAL, Mr. GANESH P. PRAJAPATSTPS.Mr.B.P.Gautam(SE), Mr.G.l.Garg(XEN), Mr.H.kTomar(AEN)For their valuable lectures and their contribution. They not Only delivered me the practicalknowledge but also provided parental attitude towards me during my practical work. Thanks aredue to all Engineers and working staff and my college department without the help of which Iwould not be reach at this point.I am equally obliged to all those Engineers Technical personnel and operators at S.T.P.S. whogave me their valuable time and rendered practical knowledge in my training period. And at lastI want to thank my colleagues. Without their help guidance and suggestions it was not possibleto produce this training report. iii
    • CONTENTSerial No. Title Page No. I Main page i II Certificate ii III Acknowledgement iii IV Contents iv-v V List of Figures vi VI List of Tables vii VII Abbreviation viii 1. SURATGARH SUPER POWER STATION 1-3 1.1 An Introduction 1-2 1.2 Future Expension 1.3 Installed Capacity 2. PLANT FAMILIARIZATION 2.1 Turbine 2.2 Boiler 2.3 Condenser. 2.4 Coal Handling Plant 2.5 Ash Handling Plant 2.6 Generator 3. CONTROL AND INSTRUMENTATION CIRCLE 3.1 SWAS PACKAGE 3.2 ATRS PACKAGE 3.4 DDC PACKAGE 3.5 FSSS PACKAGE iv
    • LIST OF FIGURESSerial No. Title Page No. 1. Combined Cycle Process 6 2. Bratyon cycle 8 3. Combustion chamber 11 4. Layout of Gas Turbine 12 5. Gas Turbine & Generator 15 6. Waste heat recovery boiler 18 7. Rankine Vapour power cycle 22 8. Rankine cycle 23 9. Combined Turbine &Generator 26 10. Switchyard 32 11. Isolator 33 12. Circuit Breaker 34 13. Lighting Arrester 35 14. Current Transformer 35 15. Potential Transformer 36 16. Protective Relays 36 17. Bucchloz Relay 40 v
    • LIST OF TABLESSerial no. TABLE Page No. 1. Coal based power plant 4 2. Coal based power plant(joint ventures) 5 3. Gas based power plant 5 4. Technical specification of compressor 10 5. Technical specification of Gas Turbine 13 6. Technical specification of Generator 14 7. Technical specification of of gas 28 8. Technical specification of generator transforme r 41 9. Technical specification of auxiliary transformer 42 vi
    • ABBREVIATION 1. SURATGARH SUPER POWER STATION1.1 An IntroductionSuratgarh thermal power station is the first super thermal plant of rajasthan.Suratgarh SuperThermal Power Station is owned by Rajasthan RajyaVidhyutUtpadan Nigam Ltd. and is situatednear village riyanwali about 25 KM from Suratgarh town, an ideal location for setting up athermal power station in the state having regards to the availability of land, water, transmissionnetwork proximity to broad gauge railway and being an important load centre for north westRajasthan. The techno-economic clearance for the prefect was issued by CEA in June 1991 – theplanning commission accorded investment sanction for the project in Nov. 91 for a totalestimated cost of Rs. 1253.31 crores on prices prevailing in Sept. 1990. vii
    • The updated cost of the project is estimate at Rs. 2300 crores of including IDC. It has generationcapacity of 1500 MW and installed with six Units of 250 MW each. It is a coal base thermalstation. Water and coal required in a large amount. Coal isreceived here from coal-fields of MPareas through railways and water is receivedfrom INDIRA GANDHI CANAL. The supply ofcoal is from MP, Jarkhandby rail. About 18000 tonne coal required per day for whole unit andeach unit consumes 150tonnes coal per day. About 2x3 km2 area covered by plant andapproximately 1800 employees works in aplant including chief engineer to labour. The supplyelectricity to the northernRajasthan, Ratangarh, Bikaner, Ganganagar.1.2 FUTURE EXPENSIONIt has been decided to set up 2 X 660 MW super critical units (Unit # 7 & 8) atSSTPS. For thispurpose about 446 Hectare land has been identified adjacent to theexisting 6 X 250 MW plant.This land is under process of acquisition. M/s TEC havebeen appointed consulting engineers forthis project. The state Govt. has also accorded its inpriciple approval for setting up in future, twoadditional units of 2 X 660 MW (UNIT # 9& 10) also based on super critical technology.1,3 INSTALLED CAPACITYFollowing is the unit wise capacity of the plant:Stage Unit NO. Installed Date of Comisioning Status Capacity(MW)Stage I 1 May,1998 Running 250Stage I 2 March, 2000 Running 250Stage II 3 October, 2001 Running 250Stage II 4 March, 2002 Running 250Stage III 5 June, 2003 Running 250Stage IV 6 May,2010Running 250 viii
    • 1.3.1 SANCTION OF SCHEMES (STAGE-I to V)Stage Unit No. Capacity (MW) Cost (Rs.Crore)1 1&2 2*250 23002 3&4 2*250 20573 5 1*250 7534 6 1*250 1117 Total 51271.3.2 COMMISIONING TARGETS AND ACHIEVEMENTSUnits Zero Date Target Actual Date Date of Date of Remark Coal Firing Commercial Operation1. June-1991 Mar.-1997 10-May- 04-Oct-1998 01-Feb-1998 19982. June-1991 Sep-2000 28-Mar-2000 07-Jun-2000 01-Oct-2000 Commissioned 6 month ahead of schedule3. Jun-1999 Mar-2002 29-Oct-2001 08-Dec-2001 15-Jan-2002 Commissioned 6 month ahead of schedule4. Jan-1999 Sep-2002 25-Mar-2002 17-Jun-2002 19-Aug-2003 Commissioned 6 month ahead of schedule5. Feb-2001 Jun-2003 30-Jun-2003 30-Jun-2003 19-Aug-2003 Commissioned of 29 month6. Jun-2006 Oct-2008 31-Mar-2009 24-Aug-09 30-Dec-2009PLANT OVERVIEW:- ix
    • 2. PLANT FAMILIARIZATION x
    • 2.1 TURBINE2.1.1 Introduction:Steam turbine is a rotating machine which CONVERTS HEAT ENERGY OFSTEAM TO MECHANICAL ENERGY.In India, steam turbines of different capacities, varying from 15 MW to 500MW, are employed in the field of thermal power generation.2.1.2 Basic Principles:The Thermal Power Plants with steam turbine uses Rankine cycle. Rankine cycle is avapour power cycle having two basic characteristics:1. The working fluid is a condensable vapour which is in liquid phase during partof the cycle and2. The cycle consists of a succession of steady flow processes, with eachprocesses carried out in a separate component specially designed for thepurpose. Each constitute an open system, and all the components areconnected in series so that as the fluid circulates through the power plant eachfluid element passes through a cycle of mechanical and thermodynamicstages.The turbine is of tandem compound design with separate HP, IP and LP cylinder.The HP & IP turbines are of single flow type while LP turbine is of double flow type;the turbine is condensing type with single reheat. It is basically engineered onreaction principle with throttle governing. The stages are arranged in HP, IP and LPturbines, driving alternating current full capacity Turbo generators.2.1.3 SpecificationType - Tandem compound condensing ReactionRated output of turbine - 250 KWRated speed - 3000 RPMMain steam temperature - 537 CRated pressure - 150 kg/cm2.1.4 TURBINE COMONENTS xi
    • Casing or Cylinders:A casing is essentially a pressure vessel which must be capable of withstanding the maximumworking pressure and temperature that can beproduced within it. The working pressure aspectsdemand thicker and thicker casingand the temperature aspects demand thinner and thinnercasings. 1. H.P Turbine Casing: The principal parts of the HP turbine casing are andaxially split inner shell, enclosing the rotor and outer shell of a barrel-typeconstruction. The barrel type of cylinder construction ensures symmetry of thewall thickness around the axis of rotation and hence the wall thickness itself isrelatively less than that used in other type of construction. 2. I.P. Turbine Casing: The IP turbine is split axially and is of single shelldesign. The outer casing accommodates a double flow inner casing. Thesteam coming from the reheater is passed into the inner casing via admissionbranches which are symmetrically arranged in the top and bottom halves ofthe outer casing. 3. L.P Turbine Casing: The LP turbine is of double flow type. The casing is oftriple shell, fabricated construction. The outer casing consists of the front andrear end walls, two longitudinal girders and a top cover. The inner shell of theinner casing acts as the guide blade carriers for the initial stages of theturbine. The guide blade carriers of the LP stage groups are so designed that,together with the inner casing, they form annular ducts which are used forextractions.2.1.5 TURBINE GOVERNING SYSTEMThe main purpose of governor is to maintain this desired speed of turbine during fluctuations ofload on thegenerator by varying steam input to the turbine.The governing system in addition toensuring the fallingload-speed characteristics of the turbine also ensures the following functions:1. The run up the turbine from rest to rated speed and synchronizing with the grid.2. Meeting the system load variations in a predetermined manner, when running in parallel withother machines.3. Protecting the machine by reducing the load or shutting off completely in abnormal andemergency situations. The governing system also includes other devices to protect the turbinefrom abnormal condition that may arise during operation. xii
    • 2.1.5.1 By-pass Governing:In this system, in general, the steam is supplied through aprimary valve and is adequate to meet amajor fraction of the maximum loadwhich is called economic load loads less than this, theregulation is done bythrottling steam through this valve. When the load on the turbine exceedsthiseconomic load which can be developed by the unthrttole full flow through theprimary valve,a secondary valve, is opened and throttled steam is supplieddownstream, bypassing the first stageand some high-pressure stages. Thissteam joins the partially spent steam admitted through theprimary valve,developing additional blade torque to meet the increased load.2.1.5.2 Governing of Reheat Turbine:In reheat turbines in cases of partial of full load ow off even after the HP control valves are fullyclosed the entrained steam in the reheatersand hot reheat line is more than enough to speed upthe turbine above over speedlimits. Hence it is necessary to provide stop valves and interceptorvalves on hotreheat line before IP turbine. While the stop valve is operated controlled similar toHP control valve but at a higher speed range by a secondary of pre-emergencygovernor as it iscalled. The valve remains full open at rated speed and startsclosing at about 3% overspeed and isfully closed at about 5% over speed.. xiii
    • 2.2 BOILER2.2.1 Introduction:The boiler is the main part of any thermal power plant. It converts the fuel energy intosteamenergy. The fuel may be furnace oil, diesel oil, natural gas or coal. The boilersmay be fired fromthe multiple fuels.The boiler installed in S.T.P.S. are made by M/s BHEL . Each of the boilersare singledrum, tangential fired water tube naturally circulated over hanged, balanced draft,drybottom reheat type and is designed for pulverizing coal firing with a max. Continuous steamoutput of 375 tons/hour at 138 kg/cm2 pressure and 540 degreecent. Temp. The thermalefficiency of each boiler at MCR is 86.8 %. Four no. Of bowlmills have been installed for eachboiler. Oil burners are provided for initial start upand stabilization of low load .Two E.S.P. (onefor each boiler) is arranged to handle flue gases from the respective boilers. The gases fromE.S.P.aredischarged through180 meters high chimney. I.D. fan and a motor is provided near thechimney toinduce the flue gases.2.2.2 Circulation System:It is essential to provide an adequate flow of water and/or of water-steam mixture for an efficienttransfer of heat from furnace to the working fluidand to prevent ‘burn-outs’. This is irrespectiveof the mode of circulation being used.In STPS NATURAL type of circulation system are used.2.2.2.1 Natural Circulation:In this type, no external pumping device is used for the movement of the fluid.The difference indensities in contents of fluids in down comers from the drum andrisers in the furnaces is used toeffect the movement of fluids. This type of circulationis employed in most of the utilityboiler.The movement of the steam and water will increase with increased heat inputto amaximum value or so called end point, after which further increase in heatabsorption will resultin a decrease in flow. One of the characteristics of natural circulation is its tendency to providethe highestflow in the tubes with the greatest heat absorption. xiv
    • 2.2.3 Heat Transfer in BoilerIn boiler heat energy is released from the combustion of fossil fuels and theheat is transferred todifferent fluids in the system and a part of it is lost or left out asunutilized.There are three modes of heat transfer :1. Conduction2. Convection3. RadiationHeat energy is transferred from a heat source to a heat receiver by one ormore of these modes forwhich heat source should be at a higher temperature thanthe receiver. In superheater tube withhigh temperature region but does not directly viewthe flame. Here the heat is transferred fromflue gas to superheater tube metal byconvection and by non-luminous radiation and in the tubemetal by conduction and tothe steam by forced convection. The power plant boilers are largecapacity steam generators used purely forthe electrical power generation. xv
    • 2.2.4 Boiler Pressure Parts:2.2.4.1 Economizer:Economiser is a feed water heater.It uses the heat produced by the flue gases forthis purpose.Thefeed water is passed through the economiserbefore supplying it tothe boiler and economiserabsorbs a part of heat from the flue gas to increase thetemperature of the feed water.2.2.4.2 Super Heater:The steam produced in the boiler has got moisture content so it is dried andsuperheated (ie steamtemperature is increased above boiling point of water)by the flue gases on the way tochimney.Super heating ensures two benefits at first theoverall efficiency of the system isincreased and secondly the corrosion to the turbine blades due to condensation in later stages isprevented.The superheated steam fromsuperheater is fed to steam turbine by means of a mainvalve.2.2.4.3 Steam Flow:Saturated dry steam from the drum follows the course that is:Steam cooled wall roof tubes –steam cooled side wall tubes – extended steamcooled side wall tubes – front steam cooled wall tubes – steam cooled roof andrear wall tubes- super heater rear horizontal assemblies – super heater de-superheater- platen super heater – pendant super heater.Super heated steam from the pendant super heater outlet header goes to the turbine via the mainsteam lines. After passing through the high-pressure stages of the turbine, steam is returned tothe re-heater via the cold reheat lines. The reheat de-super heaters are located in the cold reheatlines.Reheat flow through the unit is as follows:Front pendant re heater – rear pendant re-heater. After being reheated to the design temperature,the reheated steam is returned to the low-pressure section of the turbine via the hot reheat line.2.2.4.4 Reheater:Reheater are provided to raise the temperature of the steam from which partof energy alreadybeen extracted by HP turbine xvi
    • .The reheater is composed of two stages or section, the front pendant verticalspaced platensection and the rea5r pendant vertical spaced platen section.The rear pendant vertical spacedsection is located above the furnace archbetween the water- cooled screen tubes and rear waterwall hanger tubes. The front pendant vertical spaced plated section is located between therearwaterwall hanger tubes and the superheated platen section.All reheater drains and vents areopened before lighting off.2.2.5 Water Colled Furnaces:Bharat Heavy Electrical Limited has developed the modern water-cooled furnace. Furnace is theprimary part of boiler where the chemical energy available in the fuelis converted to thermalenergy by combustion. Furnace is designed for efficient andcomplete combustion. Major factorsthat assist for efficient combustion are time ofresidence (fuel) inside the furnace, temperatureinside the furnace and turbulencewhich causes rapid mixing between fuel and air.It has following Advantage: xvii
    • In furnace not only combustion but also heat transfer is taking placesimultaneously.The maintenance work involved in repairing the fire bricks is practicallyeliminated.Due to heat transfer in the furnace the flue gas leaving the furnaces isreduced to the acceptablelevel to the superheating surfaces.2.2.6 Soot Blower:Steam has mainly been used as the soot blowing medium, but recently theused low-pressure airas a soot blowing medium has been introduced as this offers anumber of advantage.2.2.7 Air and Gas Path:2.2.7.1 General:The total air flow through the unit is handled by two numbers axial reactionforced draft fans andtwo numbers axial reaction primary air fans. The flue gasproduced in the furnace fromcombustion of fuel is evacuated by two numbers radialdouble suction Induced draft fans. Theschematic of air and flue gas system isenclosed.2.2.7.2 Air System: 1.Combustion Air (Secondary Air): The forced draft fans supply therequired secondary air for combustion. This air is preheated by two no. RPAH. Control of secondary air flow is done byFD fan blade pitch control. The distribution of hot secondary air to the wind boxcompartments is controlled by “Secondary air dampers”. 2. Air for Drying and Transportation of pulverized coal (Primary Air): Thecold primary air fans supply the air required for drying the coal in the tubemills/mixing box and for transporting the pulverized fuel from both ends of thetube mill to the coal burners. The primary air is heated in the primary sectorsof the Rotary RAPH. The control for the primary air pressure is achieved through PA fan inletdampers. 3.Scanner Cooling Air: Each boiler is provided with 20 no. VISIBLE LIGHTSCANNER. The two no. of scanner air fans are provided to supply therequired air for cooling these flame scanners. The supply of air is taken fromFD fan discharge. The air is filtered and boosted to the required pressure bythe scanner air fans. xviii
    • Additionally an emergency air supply connection fromatmosphere is provided for supplying the cooling air to the scanners in caseboth FD fans trip. 4.Seal Air: Six no. of seal air fans are (2 nos. per mill) are provided for eachboiler. The sealing air is required for mill trunounim mill discharges valves andgravimetric feeders, of the two seal air fans provided for each tube mill, one isin operation and the other standby. The seal air takes suction from theatmosphere.2.2.7.3 Gas System:The flue gases produced in the furnace as a result of combustion, travels upward in the furnace,across the horizontal pass and downward throughthe second pass of the boiler to the airpreheater.Two no. of Induced draft fans are provided to evacuate the flue gasfrom furnace to thechimney. The ID fans are provided with hydraulic coupling and inlet damper control.PRESERVATION OF BOILERS: Atmospheric corrosion of ferrous materials proceedsrapidly in the presenceof oxygen and moisture. The oxides produced are objectionable and canbetransported to critical heat transfer areas as well as to the turbine. Pit type corrosioncan alsooccur in walls. In large boilers, with numerous complex circuits and bends, itis practicallyimpossible to completely dry the boiler in preparation for storage.2.2.8 FUEL OIL BURNING SYSTEM:2.2.8.1 Fuel Oil Atomization:Atomizes the process of spraying the fuel oil into fine mist, for better mixing of the fuel with thecombustion air. While passing through the spraynozzles of the oil gun, the pressure energy of theoil converts into velocity energy,which breaks up the oil stream into fine particles. forsatisfactory atomization theviscosity shall be less than 15-20 centistokes.2.2.8.2 Air Colled Oil Guns:The atomized assembly of an operating oil gun is protected from the hot furnace radiation by theflowing fuel oil and steam which keeps it relativelycool. The oil gun assemblies supplied for thisproject have been designed for aircooing provision. xix
    • 2.2.9 AIR PREHEATER:Air preheater is a heat exchanger in which air temp. is raised by transferring heatfrom otherfluids such as flue gas . Since air heater can be successfully employed toreclaim heat from fluegas at lower temp. level ,then it is possible with economizer theheat ejected to chimney can bereduced to a great extent thus increasing the efficiencyof a boiler.Specification:1. Heating element - Hot end, Hot intermediate, Cold end Materials - Carbon &Corten steel2. Rotor main drive motor - 11 kW, 1450 rpm, 50 Hz Coupling - Fluid coupling 11.5 fcu3.BearingGuide bearing : Spherical roller bearing Support bearing : Spherical roller thrust Thermostat: Burling thermostat4.Oil capacityGuide brg. Housing : 25 lt.Support Brg. Housing: 150 lt.Steam Coil AirpreheaterNumber of steam Coil APH : 2 Nos per boilerInstalled position : VerticalDesign Pressure : 20 kg/cm2Design Temperature : 2500CWeight of One steam coil APH : 1950 kg.2.3 CONDENSER:2.3.1 The functions of condenser are:1. To provide lowest economic heat rejection temperature from the steam. Thussaving on steamrequired per unit of electricity.2. To convert exhaust steams to water for reuse this saving on feed waterrequirement.3. Deaeration of make-up water introduced in the condenser.4. To form a convenient point for introducing makes up water.IN STPS RVUN SURFACE CONDESER is used xx
    • Surface Condenser:This type is generally used for modern steam turbine installations. Condensation of exhauststeam takes place on the outer surface of the tubes, whichare cooled by water flowing insidethem. The condenser essentially consists of a shell, which encloses the steam space.Tubescarrying cooling water pass through the steam space. The tubes are supplied coolingwaterform inlet water box on one side and discharged, after taking away heat formthe steam, to theoutlet water box on the other side.Instead of one inlet and one outlet water boxes, the may be twoor more pair ofseparate inlet-outlet water boxes, each supplying cooling water to a separatebundleof tubes. This enables cleaning and maintenance of part of the tubes while turbinecan bekept running on a reduced load.2.3.2 Description of Condenser:The condenser group consists of two condensers, each connected with exhaust partof lowpressure casing. A by-pass branch pipe has interconnected these woecondensers. The condenserhas been designed to create vacuum at the exhaust ofsteam turbine and to provide purecondensate for reusing as feed water for the boilers. The tube layout of condenser has beenarranged to ensure efficient heattransfer from steam to cooking water passing through the tubes,and at the sametime the resistance to flow of steam has been reduced to the barestminimum.350% capacity condensate pumping sets are installed for pumping the condensatefromcondenser to the deaerator4 through low-pressure heaters. Two pumps are fornormal operationand one works as stand by pump.2.3.3 Material for Condenser Tubes:Selection of tube material mainly on the quality of cooling water and thecost. Coppers alloys arepreferred as copper has very high heat transfer coefficient.But as copper has very littlemechanical strength; it has to be reinforced by alloyingwith other metals. Stainless steel tubeshas also been used and has good corrosion resistance thoughheat transfer coefficient is quitelower htan the copper alloy. xxi
    • 2.3.4 Regenerative Feed Heating System:If steam is bled from a turbine and is made to give up its latent and any superheat itmay possess,to a heater this system is called regenerative, because the fluid givesup heat, which would beotherwise wasted, to the fluid whilst in another state to raiseits temperature. The highesttheoretical temperature to which the feed water may beraised in the heater is the saturationtemperature of the bled steam. There is anoptimum point at which the steam is bled form theturbine once a feed temperature isselected, a tapping point near the stop valve produces no gainin efficiency as practically live steam is used for heating.2.3.5 Regenerative System of 250 MW unit:The regenerative system of the turbine consists of four low-pressure heaters, twogland coolers,one deaerator and three high-pressure heaters. The condense isdrawn by condensate pumps fromthe hot well of condenser and is pumped to thedeaerator through gland coolers and low pressureheaters where it is progressivelyheated up by the steam extracted from seals and bled points ofthe turbine. The drainof condensate steam on LP heaters No. 2,3 and 4 flows in cascade and isultimatelypumped into the main condenasate line after heater No.2 or flows to condenser.Thefeed water after being deaerated in the deraerator is drawn buy the boiler feed pumpandpumped to boiler through high pressure heaters where it is heated up by the bledsteam from theturbine. The drain of condensed steam of HP heaters flows in cascade and under normal loadconditions flows to the deaerator.2.3.6 HP-LP BYPASS SYSTEM: xxii
    • xxiii